1. Field of the Invention
The present invention relates to a signal encoding apparatus, a signal decoding apparatus, and a signal processing system, and more particularly, to a signal encoding apparatus for encoding frequency components generated based on an input signal, a method of processing the same, and a program for allowing a computer to execute the method.
2. Description of the Related Art
In general, in an acoustic signal encoding apparatus which encodes an acoustic signal in the related art, the acoustic signal is converted into frequency components which are normalized and quantized, and the normalized quantization value is encoded. For example, a system which divides the frequency component in the acoustic signal in each predetermined band and quantizes the signal divided in each predetermined band is disclosed (refer to FIG. 1 of Japanese Patent No. 3277692).
In the aforementioned technology of the related art, the frequency components of the acoustic signal are quantized in each of predetermined subbands, so that quantization accuracy can be controlled with respect to each subband. Therefore, the quantization can be performed by using characteristics of human auditory perception such as a masking effect. However, in the case where the quantization is performed with respect to each subband, since the occurrence probability distribution of the quantization value is different among the subbands, the encoding efficiency greatly decreases in some occurrence probability distribution of the quantization value. Therefore, the compression rate of the acoustic signal may deteriorate.